This is the story of how the rebels stole the
plans to the original "Death Star" - a space station the size of a
small moon with a weapon powerful enough to destroy a planet.

If we could get our hands on those
plans, could we build a similar fortress?

I decided to try and work
out some aspects of how a Death Star might actually work. In
Star Wars lore,
the 120km (75-mile) diameter space station was made from quadanium
steel (a fictional metal alloy) and crewed by 2m Imperial personnel,
including officers, Stormtroopers and TIE pilots.

So, would it possible in the real world?
Let's not worry about the vast quantities of raw materials required.

For example, at current production rates of steel it would take 182
times the current age of the universe to accrue enough. I'm more
concerned conceptually with how to power such a colossal battle
station and how to generate gravity for everyone on board. It turns
out our conventional technologies might not cut it.

Even if we had 100% efficient solar panels covering the much
larger Death Star, we'd still be a factor of 45 times short of the ISS's power requirements per unit volume. Not to mention that power
would severely diminish if we took the space station further away
from the sun.

You might think we could learn lessons
from the sci-fi classic
2001 - A Space Odyssey
in terms of the gravity and just spin the Death Star to create
artificial gravity via centrifugal forces.

To replicate the gravity
on Earth (9.81 meters per second squared or 1 g), the
station would only need to revolve once every 3.5 minutes, which
doesn't sound too absurd.

But there was a reason the station was
ring-shaped in 2001. The centrifugal force is proportional to the
radius of your circular path. As you travel either towards the
centre of the station or towards the poles, this radius decreases
meaning the artificial gravity would start to vanish.

If indeed
gravity was created this way, it calls into question the Death
Star's spherical design.

What if at the heart of the Death Star is an artificial
star? Surely that would solve the gravity problem?

This makes the
station something of a
Dyson sphere, the sort of technological mega-structure physicist
Freeman Dyson imagined advanced civilizations might be able to build
to harness all the energy from their stars.

However,
Dyson spheres
of the rigid shell variety usually run into problems from being
under immense stresses due to the gravitational forces.

Even if the
sphere isn't ripped apart by this, just a small push certainly would
be enough to send the structure crashing into its star.

But Dyson spheres are usually imagined
to be the size of the Earth's orbit around the sun.

For a much
smaller Death Star, most of the problems with the Dyson sphere go
away. The 13.2km diameter reactor core would only require a mass 370
times less than our moon's.

It turns out while steel and titanium
would just about fail under these conditions, the wonder material
graphene, for example, could easily withstand
the gravitational forces involved.

And we wouldn't actually need a real
star at the centre of the station - the future technology of nuclear
fusion could easily provide enough power.

While at the moment we
tend to put more energy in than we get out in our fusion
experiments, many plasma physicists think the key is going bigger
and hope that the ITER experiment,
which will be one-third of the volume of an Olympic swimming pool,
will turn the tide in this regard.

If successful, we could expect
power from our Death Star up to two million times that consumed by
the entire human race.

But there are still problems. The
pressures involved inside our Death Star reactor would be immense.
The artificial star's own gravity would not be enough to contain the
fusion plasma, so we would need something extra.

As we've learned from thinking
about lightsabers, magnetic
fields could provide the solution.

The only snag is that we'd need
some of the strongest magnetic fields in the universe - a million
times greater than we've ever created on Earth and comparable to
those of
magnetars
- a type of neutron star with an extremely powerful
magnetic field.

Back to the drawing board it seems,
unless I can get my hands on those plans…